Root crop harvestors are used to lift, clean and load sugar beets onto transport vehicles. The harvestors have beet lifting wheels that lift the beets from the soil along with a considerable amount of soil which must be separated from the beets. Under wet soil conditions, the soil will stick and build up on the grab roller assembly causing considerable strain on the parts of the harvestor as well as substantially increasing the power requirements to operate the harvestor. The harvestor must be periodically shut down to clean the mud and soil from the grab roller assembly to provide for an efficient and effective operation of the harvestor. Examples of sugar beet harvestors having grab roller assemblies are shown by E. C. Rollins in U.S. Pat. No. 3,399,766 and F. W. Eisenhardt in U.S. Pat. No. 4,049,058.